A Primer on Heated Floors – Basic Info You Should Know

Imagine waking up, climbing out of bed, and stepping not onto ice blocks that are your morning floorboards but instead onto a comfortably warm floor. Sounds nice, doesn’t it, especially at the approach of cooler fall, and then downright icy winter, weather. The way to achieve this toasty method of home heating is through underfloor heating. If it sounds complicated and intimidating, read on – you might be surprised to learn that it’s not that far out of reach for even the most traditional minds.

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UNDERFLOOR HEATING: DEFINITION

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Underfloor heating (and cooling, although this article focuses on the heating aspects solely) is, in a nutshell, a form of central heating that achieves indoor climate (temperature) control using conduction, radiation, and convection. Underfloor heating is also commonly known as radiant heating, simply because radiation is responsible for much of the heat felt. (Although this is technically not always the case.)

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Other common terms for underfloor heating include heated floors, in-floor heating, electric floor heating, or floor heating systems.

UNDERFLOOR HEATING: HOW IT WORKS & TYPES OF SYSTEMS

History of underfloor heating.

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Did you know that, although it sounds terribly modern and technical, underfloor heating actually dates back hundreds, by some counts thousands, of years? The Romans, for example, warmed rooms in their homes by running the flues for their “basement” fires, tended religiously by slaves, under elevated floors of marble.

How it works today.

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Fast-forward to today. In a modern radiant heating system, heat is supplied by electric wires or hot water tubes that are buried under the floor. As the thermal radiation rises up and out of the floor, they warm up everything they touch, which items then radiate heat as well. While the air temperature in an underfloor heating system tends to remain pretty constant, you will feel and stay comfortably warm because the surfaces you touch are warm, which means they won’t steal warmth from you.

Electric radiant heating.

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This form of underfloor heating involves the zigzagging of loops of wire into the floor of a single room, such as the kitchen, bathroom, or a bedroom. This method is often used for retrofitting.

Hot water (hydronic) radiant heating.

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This form of underfloor heating involves circulating water from a boiler through flexible tubing that has been installed in the floor (e.g., on top of the subfloor in grooved panels, clipped to the underside of the floor, or embedded into poured concrete).

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Once in place, hot water radiant heating tubing can be covered up with most types of flooring, although carpet isn’t ideal due to its insulative qualities, which end up counteracting the whole heating idea. Although the upfront installation costs are more, hot water radiant heating is the most popular and cost-effective way to heat a whole house – this system can be up to 30% more efficient than forced-air heating.

UNDERFLOOR HEATING: ADVANTAGES

1. Underfloor heating is invisible.

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Let’s face it – no one wants to have to work around the architectural constraints of conventional forced-air heating systems, whether they be boiler baseboards, radiators, or even heating vents. One of the best parts about underfloor heating is that it’s truly invisible – no evidence that it’s there, except for the nice, even blanket of warmth exuding from the floor when you need it. Mmmmm…

2. Underfloor heating is highly efficient.

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Who doesn’t like to reduce energy costs while still enjoying the benefits of, well, energy use? Underfloor heating does just that. Because it’s not trying (and failing) to heat the entire airspace of a room like a conventional heating system, cycling through a hot-air/no-air/hot-air cycle to maintain a tiny temperature range, underfloor heating is a much more efficient way to heat the house…and a great way to decrease energy bills.

3. Underfloor heating is comfortable.

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Where other traditional house-heating methods can leave patches of draftiness or downright chilliness (think hallways, or corners of large rooms), underfloor heating is evenly dispersed and consistent. Kind of like an electric blanket, just under the floor.

4. Underfloor heating can be zoned.

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This means that you can control the temperature of different parts of your house individually. The kitchen floor can be nice and cozy all day, while the spare guest bedroom doesn’t get warmed as much. This goes back to an energy-efficient benefit.

5. Underfloor heating can improve indoor air quality.

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Because homeowners don’t need to worry about stereotypically cold flooring surfaces (think tile, slate, or concrete) with and underfloor heating system, they can choose those materials with very low VOC emissions. Additionally, underfloor heating helps with moisture control and inhibits mold and bacteria growth. Studies have shown underfloor heating to be a benefit to combatting many common household allergens.

UNDERFLOOR HEATING: DISADVANTAGES

1. Underfloor heating costs more upfront.

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Retrofitting or installing a new underfloor heating system costs about 50% more (for a hot water, or hydronic, system) than putting in a conventional forced-air heating system. Energy savings afterward are pretty great, but you’ll need a bigger chunk of change in the beginning. Average range for installation is from $6 to $15 per square foot.

2. Underfloor heating can take a while to heat up.

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While you immediately feel the hot air blowing from a conventional forced-air heating system, an underfloor heating system takes a bit longer to warm up. (Once running, of course, the underfloor heat is more consistent and effective.)

3. Underfloor heating may require strategic furniture placement.

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Pianos, for example, may be affected by continuous warmth from an underfloor heating system, so it is recommended that they are placed on insulation. This could be a stylistic deterrent for some people.

4. Underfloor heating is not easily changed once installed.

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The system must be well designed from the get-go, because it is neither practical nor inexpensive to go in and change an underfloor heating system once it’s in place.